Scientists at Ohio State University have taken a thermoelectric material that's been used for decades to power deep-space probes, and worked out how to double its efficiency. That's good news: thermoelectrics convert heat directly into electrical energy. By catching exhaust heat, the new material may allow car alternators to be replaced... and that'll push up the efficiency of car engines. The team doped lead telluride with tiny amounts of thallium, which adjusts the crystal structure and increases its heat-electricity conversion efficiency from around 6% to over 10%. Even better, since engineers have years of experience of working with lead telluride, it should be easy to commercialize the product. Environmentalists will have to be pleased, and relax about the high toxicity of thallium, though. [Technology Review]